Step-by-step motor



April 28, 1925.

P. VAN SANTEN KOLFF STEP BY STEP MOTOR Filed March 11, 1922 2 Sheets-Sheet 1 April 28, 1925.

P. VAN SANTEN KOLFF Y 2 Sheets-Sheet 2 @Lbboump.

Patented Apr. 28, 1925.

STEP-BY-STEP MOTOR.

Application filed March 11, 1922. swarm). 543,058.

To all whom it may concern:

Be it known that I, PETRUS VAN SANTEN KoLrr, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Step-by-Step Motors, of which the following is a specification.

y invention relates to that class of apparatus for electrically transmitting signals or conveying intelligence from one point to another a distance away in which a 'stepby step motor is employed as a receiver.

e present invention has, as its object a stepby step motor simple in. construction and operation and accurate and reliable inits function.

In order to fully explain the principle of operation and the advantages of the invention reference is made to the accompanying drawings in which ig. 1 is a vertical section through an apparatus embodying the invent-ion;

Fig. 2 is a plan-view thereof;

ig. 3 is a wiring diagram indicating in a general way the electrical connections for operating oneor a plurality of motors;

Fig. 4 is a iagrammatic representation of the principal parts of the invention and Figs. 5 and 6 are a fragmentary plan view and section, respectively, of a modified form of construction embodying the invention.

Having reference to Figs. 1 and 2, 10 is a casing containing a base plate 11 of insulating material. is secured by means of screws 12 a frame comprising a bottom plate 13 of soft steel, a top plate 14 of soft steel and spacing columns 15 of soft iron, preferably brassplated.

Upon the plate 13 are mounted three solenoids 16 spaced 120 apart and containing each an iron core 17. The solenoids are secured to the plate 13 by means of screws 18 or in any other suitable manner.

Three similar solenoids 19 containing cores 20 are secured to the top plate 14 in alignment with the lower set of solenoids. As indicated in Fig. 1, the solenoids 16 and the solenoids 19 are interconnected in pairs by pair of solenoids forms part of an individual electric circuit for separately energizing the solenoids, as will be more fully pointed out.

. tongues are substantially flush with Upon the base plate 11- connections 19 and each Through the top plate 14 centrally tween the solenoids extends a shaft 21 carrying at its upper end its lower end a brass disk 23 having a relainserts 24, preferably ft iron in closely spaced relation adjacent its peripheral e ge. Theshaft 21 is surrounded by a sleeve 25 of brass or other nonmagnetic material which carries at its lower end a disk 26 of like material. The flange 27 extending downwardly edge of the disk 23 and ing an upwardly extending flange 29 is connected to it to f erewith a-case for the disk 23. Both the disk 26 and the disk have angularly spaced radial slots 30 in alignment with the cores 17 and 20.

he cores project beyond the ends of the solenoids and the projecting ends are cut away to leave tongues 17- and 20 respectively fitting the slots 30 and constituting a pair of poles. The outer faces of the the inrespecaround the ner surface of the disks 26- and 28 tively.

Upon the top plate 114 is mounted in a ronze bearing 31 a shaft 32 carrying at its upper end a pointer 33 co-operating with a dial 34 which is supported upon the plate 14 by means of screws 35 and spacers 36 through a gear 38.

The casing 10 is closed on the top by a glass cover 37.

he foregoing merely indicate in tural relationship furnishes an example to a general way the strucof the principal parts of a brass disk 28 hav i the invention and of certain auxiliary deneed not be uniform. The number of inserts 24 in disk 23 may also vary within wide limits, provided that the number is sufliciently large and the angular spacing sufiiciently small to bring about small angular movements of the disk 23.

T e arrangement must generally be such that one insert is always out of alignment with a pair of poles but near enough to be tion counter, it is obvious that the invenattracted bythem when they are energized tion may be advantageously applied in all to define olesof opposite polarity. When instances where it is desire to visually inthe individual ma netic circuits are enerdicate the direction and extent of movement gized in proper or er, one of the inserts is of an element located at a place which is undrawn into the gap between the poles im inviting, inaccessible, difficult to reach or reparting angular movement to the. disk 23. mote from a desired point of observation.

\Vhen an insert reaches its final position in It is merely necessary to provide mechanism alignment with the cores, the motion ceases for translating the motion of such element, and another insert has reached a position whether it be linear motion or angular mo- 3' close to another. pair of solenoids. I tion, into motion of a switch mechanism of It is thus clear that by establishing a defithe order represented by the shaft 40, eccennite order in successively energizing the trio 41 and switches 42, 43 and 44. The different pairs of solenoids a progressive class of switch mechanisms available for step by step movement is imparted to the such purpose has wide limits as is easily un- 80 disk 23 in one direction. By reversing the derstood. order, the direction of rotation is reversed. As concrete cases in the general field of It is thus a simple matter of control to deapplication may be mentioned valve or gate termine the direction of rotation and also control in power plants, locks, sluices, dams to determine the angular position of the or the like or damper-control in large fiues 65 disk 23. or smokestacks etc.

The facility of control and accuracy of' The peculiar advantage of the form of response may be utilized in many ways and motor described is due to the accuracy of for various purposes. angular movement in response to a primary In Fig. 3 is indicated a mode of operation movement, linear or angular. By increasing 66 for using the arrangement as a revolution the number of inserts or the number of solecounter. In Fig. 3, 40 represents a shaftnoids or both and selecting an appropriate which maybe connected by suitable gearing form of control switch or suitably modify to a shaft the revolutions of which are to ing a particular form of control switch, it be counted. The shaft 40 carries an eccenis possible to obtain an indicator which is 9 trio 41 which during one revolution of shaft absolutely true for all practical purposes.

40 successively closes-three switches 42, 43 In the form of device shown in'Figs. 1 and 44. One element of each switch is conand 2, the different detail parts referred to, nected to a common connection 45 connected such as the housing of non-magnetic mawith one pole of an electric supply circuit terial including the disks 26 and 28 and the 1 50. The other elements of the switches are. sleeve 25 etc. have special utility, but connected to one end of the solenoids 46, 47 are by no means indispensable. In fact and 48 respectively, the other ends of the the invention may be carried out by radisolenoids being connected with the other cally different arrangements. It is indeed pole of the circuit 50. A three point switch not absolutely essential that the solenoids 51 may be placed intermediate the switches be in vertical alignment and it is even not 42, 43 and 44 and the solenoids for making necessary that two separate aligned solethe motor inoperative. noids be employed. It is merely necessary The solenoids 46,47 and 48 represent pairs that a plurality of angularly spaced magof solenoids 16, 19previously referred to. netic circuits are progressively established 11 For the sake of simplicity the electrical which act in cyclic order upon diflerent inconnections have not been indicated in Fig. serts as armatures and draw themintothe 1 except the series connections 19 between magnetic path thereby effecting rotation of pairs of solenoids 16, 19. In practice I prethe rotary element. Thus the magnetic cirfer to bring the free ends of the top soiecuits could be disposed to define a circular 11 noids to a common post and the free ends series of radial gaps for a hollow cylinder of the bottom solenoids to individual posts carrying the inserts. The rotary member and provide suitable terminals for the posts can in fact be a disk or it may contain a for establishing in the usual way the concylindrical portion or aconical portion passnections previously referred to. ing through gaps which are then suitably As indicated in Fig. 3 a plurality of momodified for such constructions. tors may be operated at the same time to In the foregoing the invention'has been provide a plurality of revolution counters defined in connection with rotary elements a lfi r n POmtS of v i n- I i carrying the inserts and indeed the form of needless to point out all the various modidevice described constitutes a preferred emfications which may be made in the mechanibodiment. However, within the broader ascal part of the counter for translating the poet of the invention, the element carrying motion of the disk 23 or the shaft 21. the magnetic inserts may follow different 1 While s1 ecific. reference has been made to laws of motion. To show one concrete exthe use of the invention as part of a revoluample, reference is had to Figs. 5 and 6 in which the element carrying the inserts 53 is a plate 52 supported for linear motion in guides 54. Three magnetic circuits repre-' sented by pairs of poles 55 and 56, 57 and 58, and 59 and 60 respectively, may be used, although as has been previously pointed out, four or more magnetic circuits may be used, provided that the distribution of the magnetic circuits is such thatone insert is always out of alignment with a pair of poles but near enough to be attracted thereby. While a movable element has necessarily only a limited range of motion and is to that extent not of such general application as a rotary element, it is equally useful in all cases where a movable body the position of which is to be indicated has only a limited movement. Thus the linear motion element shown in Figs. 5 and 6 may find ready application for instance in connection with gates or dampers.

The principal characteristic of all forms embodying the invention is the relation of the magnetic circuits and the segments. The magnetic lines of force pass through the movable element containing the inserts at right angle to the plane of motion and not in the plane of motion thereof asis the case in other types. The insert acted upon by one of the magnetic circuits is always close to that circuit so that the magnetic coupling is strong and produces a powerful torque with little variation between the starting torque and the final torque.

Another advantage is the unlimited number of steps obtainable by simply increasing the number of inserts or by properly ooordinating the inserts and the number of magnetic circuits. In factby appropriate design the motor, although essentially of the step by step type may outwardly appear as having a continuous motion, since the steps or increments of motion may be made very small.

' I claim: 1. A step by step motor comprising a movable member of nonmagnetic material containing magnetic elements of small extent in the direction of motion and magnetically separated from each other, a plurality of separate magnetic circuits each disposed to successively include the said magnetic elements and means for separately energizing the magnetic, circuits, the number of magnetic elements being large relatively to the number of magnetic circuits and the relative position of the magnetic elements and circuits being such that when one ma netic element is included in one magnetic circuit, another magnetic element is less than the distance between adjacent elements away from another magnetic circuit.

2. A step by step motor, comprising a rotary disk of non-magnetic material contaming along its peripheral portion magnetic elements of small angular extent magnetically separated from each other, a plurahty of magnetic circuits spaced along the said peripheral portion on opposite sides thereof so as to successively and alternately include one of the elements as a part during rotary movement and means for separately energizing the individual in cyclic order, the number of magnetic elements being large relativel to thenumber of magnetic circuits and t e relative posi tion of the magnetic elements and the circuits being such that when one magnetic element. is included in one ma etic circuit another magnetic element is ess than the distance between adjacent elements away from another circuit.

3. A step by step motor comprising a movable member of non-magnetic material containing magnetic elements of small extent in the direction of motion and magnetically separated from each other, a. plurality of separate magnetic circuits each disposed to successively include the said ma netic elements, each magnetic circuit including pole pieces on opposite sides of the movable member of substantially the same extent in the direction of motion as the magnetic elements and means forseparately energizing the magnetic circuits, the number of magnetic elements being large relatively to the number of magnetic circuits and the relative disposition of the magnetic elements and magnetic circuits being such that when one magnetic element is included in one magnetic circuit another element is less than the distance between two adjacent elements away from another magnetic circuit. 4:. A step by step motor, comprising a rotary disk of non-magnetic material containin along its peripheral portion magnetic lements of small angular extent magnetically separated from each other, a plurality of magnetic circuits spaced along the said peripheral portion on op osite sides thereof and including each pois pieces of substantially the same angular extent as the magnetic elements, and means for separately energizing the individual magnetic circuits in cyclic, order, the number of magnetic elements being large relatively to the number of magnetic circuits and the relative position of the magnetic elements and magnetic circuits being such that when one magnetic element is in alignment with one pair of pole pieces another magnetic element is less than the distance between the adjacent elements away from another gait of pole pieces.

In testimony whereof, afiix my slgnature.

PETRUS VAN SANTEN KOLFF.

magnetic circuits 

